The invention relates to the treatment of at least a portion of a biological body with magnetic fields and to an apparatus for treatment with magnetic fields.
Apparatuses are known which use pulsed or modulated magnetic fields to produce a positive influence on biological tissue. In this case, as can be found, for example, in DE 40 26 173, the tissue is subjected to a constant magnetic field and to a magnetic alternating field superimposed on it. During use of such appliances, it has been possible to show that a positive therapeutic effect can be achieved by subjecting biological tissue to magnetic fields and/or to magnetic alternating fields. The healing affect of such magnetic-field therapy appliances covers, inter alia, the alleviation of osteoporosis or the consequences of a stroke. In this case, it appears probable that the magnetic fields which are applied promote transport and/or metabolic processes which lead to a positive therapeutic effect. Until now, it has been assumed that the process described above is caused by the stimulation and/or the absorption of ion cyclotron resonances (ICR) in a biological body. However, in some circumstances, this appears to be questionable since cyclotron resonances in general occur only in free particles, for example in a vacuum or in the case of electrons in the conduction band of a semiconductor. Furthermore, a simple calculation can also be used to show that a cyclotron movement would take place on a circular path whose radius is actually greater than the average diameter of a cross section of a human body. This means that an explanation of the energy transfer based on cyclotron resonance may be questionable, particularly in the case of solid tissue. In practice, it has been found that, with the existing magnetic-field therapy appliances, it is often necessary to carry out a number of treatments initially in order in this way to define the frequencies for the subsequent treatments which cause the desired positive effect. This procedure means that therapy with magnetic fields is very complex and imprecise and only exceptionally, if at all, allows a deliberate procedure for complaints, which can be defined and located, in solid or liquid material.
The invention is thus based on the object of providing an apparatus for treatment with magnetic fields, which avoids the said disadvantages and which, in particular, for the first time allows treatments with magnetic fields to be carried out in all biological materials in a specific and reproducible manner, irrespective of whether any ionic particles are present.
This object is achieved in a very highly surprising manner just by the features of claim 1. Advantageous and preferred developments are the subject matter of the dependent claims.
In comparison to known solution attempts, the apparatus according to the invention is based on the idea that the positive treatment effect can be achieved by producing repeated spin resonance sequences.
One preferred embodiment of the invention comprises, in a particularly advantageous manner, a magnet for producing an essentially constant magnetic field, and a coil system for producing a magnetic alternating field at right angles to the magnetic field of the magnet, with this, in a manner which is obvious to a person skilled in the art, corresponding to a classical arrangement for carrying out spin resonance. Furthermore, an advantageous development of the apparatus according to the invention also has control electronics for actuation of the magnet and the coil system, which control electronics can be adjusted such that nuclear spin resonance is produced in a biological body introduced between the magnets described above. In this case, in a highly advantageous manner, the control device has an associated device by means of which parameters or intervals can be defined over a fixed treatment time period, based on which the apparatus according to the invention repeats the nuclear spin resonance process or nuclear spin absorption process controlled by the control electronics.
In the context of the invention, it has been found to be very highly advantageous if the repetition rate, that is to say the time sequence of the nuclear spin resonance is carried out, is determined as a function of the spin-lattice relaxation time T1. The spin-lattice relaxation time describes, in the form of a time constant, the exponential or logarithmic build-up of macroscopic magnetization in the direction of a magnetic field. The resonant injection of a magnetic alternating field at right angles to the said magnetic field reduces the magnetization in the direction of the magnetic field. If the resonant injection is stopped after this decrease in the magnetization, then the magnetization in the magnetic field direction builds up once again, in which case it can be assumed on the basis of the logarithmic growth that the magnetization reaches approximately 95% of the initial value of the magnetization once again after a time of approximately 3T1. This means that, after a time interval of 3T1, a new effective energy transfer can be achieved by spin resonance. The definition of the spin resonance repetition rate to be three times the spin-lattice relaxation time of the body or body part to be treated is thus ideally typical for the subject matter of the present invention, but is not essential, so that other frequencies are also feasible. Furthermore, this definition allows a positive biological effect to be achieved immediately. In contrast to the prior art, it is no longer necessary to carry out a number of comprehensive initial treatments to determine, more or less objectively, the frequency which achieves a biological effect. Since the spin resonance can be used both for gaseous molecules and for molecules which are in solution and for molecules which are incorporated in solid form, the corresponding spin-lattice relaxation times, or those required for the treatment, are also advantageously accessible by measurements.
In consequence, in a further development of the invention, the apparatus for treatment with magnetic fields comprises a further coil system. The axis of this coil system is preferably at right angles to both the axis of the magnet and the axis of the first coil system. In one preferred embodiment, this coil system is used as a detection coil system. In this case, before the start of the treatment, the spin-lattice relaxation time T1 can be determined in a very highly advantageous manner using the detection coils, for example in the course of a spin-echo measurement, and, as already described above, this allows the repetition rate to be defined.
Furthermore, in a positive further refinement of the subject matter of the invention, this subject matter has an associated evaluation device which allows the required parameter T1 to be determined from the spin-echo measurement described above. If, furthermore, the already described detection coil is also provided, then the repetition rate for the spin resonance can be obtained directly and entirely objectively, locally, for the body to be treated or body part to be treated. This means that there is no longer any need for treatment appointments which serve only to find a possible xe2x80x9ceffective frequencyxe2x80x9d. However, in a simplified embodiment in this case, this device can also advantageously be used just to record and to provide already defined values, or values which can be found in the references, for T1 or for other parameters such as the magnetic field B0, the alternating field B1, the Larmor frequency f0 or other appropriate parameters, in order in this way to define the conditions in which the treatment can be carried out by means of spin resonance.
It is also very highly advantageous if the control electronics comprise a measurement device which is able to use, for example, installed detection coils such as those already described above to measure the energy which is emitted to the tissue or the body part to be treated in the course of a sequence of nuclear spin resonances. This thus allows a relationship to be produced in a very simple way, using which it is possible to represent the relationship between the treatment success and the xe2x80x9cenergy dosexe2x80x9d emitted to the body. Appropriate recording can, in particular, be used to define specific xe2x80x9cenergy dosesxe2x80x9d for a specific application. Furthermore, alternatively, it is possible to use this for monitoring the progress of the illness. In this case, it is obvious to a person skilled in the art that such recordings can also be used in a very wide number of different ways.
In an ideal situation, it is sufficient for the spin resonance to inject a discrete frequency, namely the so-called Larmor frequency, of an alternating field in order, in the classical sense, to tilt the macroscopic magnetization or to achieve a corresponding energetic transfer. In practice, no such discrete frequency can be found. In addition, it must be expected that the magnetic field being applied is not homogeneous and that chemical shifts also result in inhomogeneities within the areas which are being treated with spin resonance so that the spins do not precess in phase at a standard Larmor frequency. In order, nevertheless, to cause as many spins as possible to be tilted, the magnetic alternating field produced by the coil system according to the invention advantageously comprises a large number of defined Fourier components.
In a positive development of the apparatus according to the invention, the magnet comprises a Helmholtz coil arrangement. Helmholtz coils are distinguished in particular by being able to produce essentially constant homogeneous magnetic fields. Furthermore, they offer the advantage that they allow field shifting to be carried out in a simple manner. This field shifting can be carried out firstly by varying the current flowing through the coils, or secondly by superimposing an additional magnetic field on the Helmholtz field by means of a further coil. A pair of Helmholtz coils thus make it simple to carry out nuclear spin resonance by field shifting.
However, in practice, it has been possible to show in a very highly advantageous development of the invention that there is no need for a Helmholtz coil arrangement such as that described above. For example, when spin resonance is being carried out for treatment purposes, it is sufficient to use a hard-ferrite magnet to produce the magnetic field. Since simple magnets can also be used, this allows the apparatus according to the invention to be produced in a considerably more advantageous manner, thus allowing the treatment with the apparatus according to the invention to be available to a large range of patients. In this context, it has advantageously been possible to show that, with magnetic field strengths of approximately 22 Gauss, a field discrepancy of up to approximately xc2x10.6 Gauss is sufficient for treatment purposes with the present invention.
This is feasible, inter alia, by superimposing an additional variable auxiliary field, by means of an auxiliary coil, on the comparatively severely fluctuating field. In this case, this auxiliary coil is actuated by a control device in such a way that the nuclear spin resonance takes place using a rapid adiabatic run procedure with a magnetic alternating field injected at a constant frequency. The adiabatic run is based, inter alia, on shifting the field of the magnetic field produced by the magnet. In this case, in one possible embodiment, the magnetic field of the magnet first of all has the magnetic field from an auxiliary coil superimposed on it additively, that is to say amplifying it, and, at the end of a resonance sequence, has the said magnetic field superimposed on it in a compensating manner, that is to say attenuating it. This means that the magnetic field of the magnet is reduced continuously during a resonance sequence. The magnetic field is preferably reduced in the form of a sawtooth. In the adiabatic run, however, it is necessary to ensure that the field variation is not carried out too quickly. Specifically, if one considers the magnetic fields and the magnetization in the reference system rotating at the Larmor frequency, then it is evident that the field superimposition within this rotating reference system results in a further Larmor movement of additional magnetization, which is superimposed on the original movement produced by the magnetic field. The field variation results in this additional magnetization changing its direction in the rotating reference system, since it is aligned with the magnetic field resulting from the superimposition. However, in this case, this takes place without any energy transfer, that is to say adiabatically, only if the variation in the magnetic field takes place sufficiently slowly. In this way, in a highly advantageous and cost-effective manner, it is possible for the spin resonance to reach all the body parts located in the active zone and to achieve an essentially optimized energy exchange, since, as a result of the shifting of the magnetic field and despite any possible discrepancy in the field density, the spins are subjected to a suitable magnetic field so that resonance can in any case occur at the transversely injected Larmor frequency.
Furthermore, it is within the scope of the invention to carry out the spin resonance not only, as described above, by field shifting but also to do this by pure frequency shifting, or to allow the energy transfer of the spin resonance to take place by means of combined field/frequency shifting. Although this does not preclude a rapid adiabatic run.